docs: def download_setuptools(version=DEFAULT_VERSION, download_base=DEFAULT_URL,
                          to_dir=os.curdir, delay=15):
      """Download distribute from a specified location and return its filename
  
      `version` should be a valid distribute version number that is available
      as an egg for download under the `download_base` URL (which should end
      with a '/'). `to_dir` is the directory where the egg will be downloaded.
      `delay` is the number of seconds to pause before an actual download
      attempt.
      """
      # making sure we use the absolute path
      to_dir = os.path.abspath(to_dir)
      try:
          from urllib.request import urlopen
      except ImportError:
          from urllib2 import urlopen
      tgz_name = "distribute-%s.tar.gz" % version
      url = download_base + tgz_name
      saveto = os.path.join(to_dir, tgz_name)
      src = dst = None
      if not os.path.exists(saveto):  # Avoid repeated downloads
          try:
              log.warn("Downloading %s", url)
              src = urlopen(url)
              # Read/write all in one block, so we don't create a corrupt file
              # if the download is interrupted.
              data = src.read()
              dst = open(saveto, "wb")
              dst.write(data)
          finally:
              if src:
                  src.close()
              if dst:
                  dst.close()
      return os.path.realpath(saveto)